D-glucans from edible mushrooms: a review on the extraction, purification and chemical characterization approaches.

D-Glucans from edible mushrooms present diversified chemical structures. The most common type consists of a backbone of β-D-glucose (1→3)-linked frequently branched at O-6 by β-D-glucose residues as side chains. However it is possible to distinguish α-, β- and mixed D-glucans. Further discrimination could be made on the basis of glycosidic bond position in a pyranoid ring, distribution of specific glycosidic bonds along the chain, branching and molecular weight. The present manuscript reviews the processes of extraction, purification and chemical characterization of D-glucans, such as NMR studies, methylation analysis, Smith degradation, and some other methodologies employed in carbohydrate chemistry characterization. In addition, these polysaccharides are important because they can provide many therapeutic benefits related to their biological activity in animals and humans, either immunostimulatory activity, inhibiting tumor growth, as well as exerting antinociceptive and anti-inflammatory action, among others, which are usually attached to their structure, molecular weight and degree of branching.